Arizona university researchers work to find new uses for copper tailings

Researchers at Arizona’s public universities are working with the state mine inspector and the mining community to discover novel ways to use leftover waste rock from copper mining, the Arizona Board of Regents (ABOR) recently announced.

A $3.6 million grant awarded by ABOR is allowing researchers to pursue the project. The grant, known as the Regents’ Research Grant, pairs public university researchers with state agencies and community organizations to address long-term challenges facing the state of Arizona.

The research team includes 13 faculty and staff from Arizona State University, the University of Arizona, and Northern Arizona University. Isabel Barton, an assistant professor of mining and geological engineering at UArizona, is the principal investigator. Misael Cabrera, the former director of the Arizona Department of Environmental Quality, will serve as the project liaison for the research plan.

Copper tailings, the technical name for the waste rock the researchers are studying, is pulverized into fine sand through the mining process. These tailings potentially contain strategic minerals such as zinc, iron, cadmium, and lead, which are in high demand as the United States seeks to reshore its supply chain and mine more of these ores domestically for use in things like electric vehicle battery manufacturing. Because tailings are already pulverized, researchers are hopeful that the process of refining these minerals would be far less expensive and onerous than it would be if they were mined traditionally.

“[R]eprocessing of mine tailings may significantly reduce costs, as the ore has already been mined, crushed and partially processed,” according to the proposal for the project.

Additionally, tailings can contribute to soil pollution and other negative environmental outcomes. Extracting tailings from mines old and new could not only bolster America and Arizona’s mining industry but also improve environmental conditions.

Researchers believe that this project is of increasing importance with copper demand forecast to increase by 275-350% by 2050. Policymakers in the U.S. have also recently focused more on the domestic extraction and refinement of minerals and other natural resources to make American supply chains more stable and less dependent upon changes in international affairs. “The extraordinary volumes of leftover rock from copper mining make reprocessing copper tailings a world-class challenge and opportunity for Arizona,” Barton said. “This large-scale interdisciplinary project represents a substantial first step toward making use of a massive, but undeveloped, potential resource.